GLC Chapter 9 Molecules
Review
1. Which type of elements are the most stable (least willing to undergo change)?
2. How many valence electrons do they have?
3. What would you expect of the other elements to increase their stability?
3 types of bonds:
1. ____________________________-valence electrons are shared equally between bonded atoms.
2. ____________________________-valence electrons are shared unequally between the bonded atoms.
3. Ionic bonds-valence electrons are transferred from one atom to another forming ions. These oppositely
charged ions attract.
Bonding between atoms is rarely purely ionic or covalent. It is usually some degree between the two.
General rule on the type of bond that forms between two atoms:
Ionic bond-____________________________
Covalent bond-__________________________________
Electronegativity Differences-Used to determine what type of bond forms (Pg. 151)
 0-.2 ____________________
 .3-1.7 __________________
 >1.7 ______________
4. Determine the type of bond with electronegativity differences:
H and Cl:
Cs and Cl:
Cl and Cl:
Molecules(___________________)-__________________________________________
______________________________
Molecular formula-shows the ________ and ____________ in a molecule of a compound
Diatomic molecule-______________________________ Ex.
Diatomic elements-___________________________________ (Memorize:_____________________)
Show the overlapping of orbitals in H2
Bond Length – _______________________________________
Bond energy – _________________________________________________________
 _________________________ – Element symbol represent the nucleus and electrons other than the valence
electrons. The dot (s) around the symbol represent the valence electrons. The ______________________that
a nonmetal can form between other elements is determined by the ______________________________.
1
Note: This is an important representation because _______________________________
______________________________________
5. Illustrate the electron dot notation for all the elements in period 2:
_________________-using electron dot notation to show the way atoms form a compound
Single bond is the ________________________________________________________
______________________________________________________________________.
Double bond – ___________________________________________________________
__________________________.
Triple bond-_____________________________________________________________
_____________________________________.
Double bonds and triple bonds are called _____________________ bonds.
Which type of bond is the strongest? Weakest?
Which bond is the strongest? Shortest?
Steps for drawing Lewis structures:
1. Determine the number of bonds needed with the following formula:
N A
 # of bonds
2
where: N = the # of needed electrons (8 for all elements except for H (2) and B (6)).
A = the # of available electrons which is the sum of all valence electrons.
2. Draw a skeleton structure. The least electronegative atom is the central atom (except for H) and you will
not be asked to draw any ringed structures.
3. Connect the atoms with the number of bonds calculated in step 1.
4. Finish by making sure all atoms in the structure have an octet of electrons (except H and B).
5. Polyatomic ions: if the ion has a negative charge remember to increase the number of available electrons
and if the ion has a positive charge remember to decrease the number of valence electrons.
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6. Draw these Lewis structures. Note if C is in the formula, it is the central atom.
NH3
CCl4
C2H6
SO3-2
H2CO
N2
O2
CO2
NH4+1
Binary Molecular Cmpd.
Naming Binary Molecular Cmpd – only ___ elements in formula
Memorize the Greek prefixes for one to ten p212
Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
1
2 3 4
5
6
7
8
9
10
Steps for naming molecular compds.
1. Less electronegative element (more metallic first), and prefix to element to show number of atoms. Omit
mono-.
2. Add prefix to root name of second element and add –ide ending.
Examples: Name the following compounds.
10. P2O5
11. CO
12. CCl4
13. N7O4
14. CO3
15. Al2S3
Draw the Lewis Dot structure for each of the following…
1. CH4
4. BH3
2. NH3
5. CH3Cl
3. CO2
6. HCN
3
4